Unmanned vehicles configured to navigate enclosed spaces, such as pipes, e.g. fluid or gas pipes, may be small. Thus the types of locomotion which may be effectively employed on such vehicles may be limited by size constraints. In some examples, a plurality of wheels positioned around a perimeter of a vehicle may be used to move the vehicle through an enclosed space. However, wheeled vehicles may be limited in use to a specific diameter pipe.
In another example, a complicated crawler system may be used. In one crawler system, a series of bumpers maintain the vehicle centrally located in a pipe. Separately, pressure pads may be used to hold one of two gripping modules stationary while a locomotion module expands or contracts to move the vehicle. However, the stroke length of the pressure pad actuators and/or the bumper length may limit the minimum or maximum diameter pipe in which the vehicle may be effectively deployed. Further, the vehicle requires separate holding mechanisms and centering devices.